Change '#### Try' to '### Alternate try'

This does not complete the alt code related headers but I noticed this
and it was easy to do quickly. Unless I run across another when I am
working on the README.md files of the entries I will probably have to do
the rest manually as I come across them as most likely the headers are
missing.

This was done as

    sgit -e 's/^#### Try/### Alternate try/g' '*README.md'

1984/mullender/README.md

@@ -58,7 +58,7 @@ overflow!
 BTW: is there such a thing as too fast a CPU ? :-) Actually yes for certain code
 which is probably not as uncommon as you think :-).
 
-#### Try:
+### Alternate try:
 
 
 ```sh
@@ -137,7 +137,7 @@ make gentab
 ./gentab file
 ```
 
-#### Try:
+### Alternate try:
 
 ```sh
 ./gentab gentab